The first rule of this seasons “plaid” trend is to keep in mind not all squares are the same.

"Checks are patterns of squares and plaid is a pattern of striped bands, mostly at right angles," explains fashion stylist Peter Papapetrou, who has worked with Hilary Duff, Dragonette, Jully Black and Javier Bardem. And when it comes to the difference between plaid and tartan, there really isn't one, at least not in North America — plaid is our preferred term. In Scotland, however, tartan denotes the pattern and plaid means a tartan blanket or over-the-shoulder cloth.

"A lot of big designers like Dolce and Gabana ... and Burburry use these patterns for day and night," comments Papapetrou.

At a retail level, it seems we can't have too much of a square thing. Plaid and checks are everywhere, from shirts, to vests, to coats, to scarves, to bags and shoes. And underwear.